I’m convinced that Congress has ordered the Capitol Police to keep the pigs away not so much due to swine flu concerns, but that Congress didn’t want any competition at the trough:

U.S. Capitol Police have rejected PETAÃ¢â‚¬â„¢s plan to bring live pigs to the Capitol because of swine flu fears.
[...]
The letter also cited Ã¢â‚¬Å“nuisance concernsÃ¢â‚¬Â with the plan by People for the Ethical Treatment of Animals (PETA) to bring a group of pigs and gallons of swine urine and tons of manure to Capitol Hill.

PETA should have registered the pigs as lobbyists and tied envelopes full of cash to their backs and they’d have been allowed in without a doubt.

Additionally, the Secret Service didn’t want the manure around, because they feared that Obama might mistake it for the health care bill and try to sign it.